The head of SafeWork SA has told an Independent Commissioner Against Corruption (ICAC) hearing its staff morale is low, as it tackles a barrage of complaints and tries to improve its processes and accountability.

Martyn Campbell took over as SafeWork executive director last year, and today gave evidence at the ICAC's public evaluation of the organisation, which was launched after a high volume of complaints.

"I've inherited an organisation that just needs to be brought into the 21st century and given some contemporary tools," he said.

Mr Campbell said he had made a wide-ranging improvements since taking over, but staff morale was low and resilience training had been rolled out.

He said there were some underperforming investigators but, due to performance management becoming a "tick and flick" exercise, they had not been told.

"Many had never been told that they were doing a fantastic job. Many had never been told they were not performing to expectation. Many had never been told that they could not or were not doing their job to an acceptable standard," Mr Campbell said.

SafeWork SA has since partnered with Charles Sturt University to develop a course for its investigators, which two-thirds of its 90 investigators have now completed.